The milestone signifies that the firm has finished designing the basic features of the new freighter platform.

“With the key features now defined our engineering team is able to focus on the detail drawings as they quickly move towards the critical design review, which is expected in March of 2014,” says AEI president Roy Sandri in a statement.

More than five customers from Mexico, Southeast Asia, Canada and the USA have put down deposits for 24 conversion slots for the aircraft type so far, says Robert Convey, AEI’s vice-president, sales and marketing.

AEI will begin making parts for the first CRJ200SF conversion in January and will begin the touch labour to modify the regional jet in June, Convey tells Flightglobal. The work will be done at Miami-based repair station Commercial Jet.

The conversion specialist plans to turn in paperwork to the US Federal Aviation Administration to approve the new freighter by the end of 2014 and expects certification by mid-2015.

The prototype for the converted aircraft has undergone some structural changes during the design review but has not undergone any major changes since the firm first officially launched the conversion programme in February, says Convey. The modified CRJ200 will feature a 2.39m (94in) by 1.96m (77in) cargo door carved into the left side of its fuselage, giving the aircraft a maximum payload of 6,080kg (6.7t).